Why are case implementations so slow?

[jh@ohio-state.arpa (Juha Hein{nen)]

Dispatching of a method is straighforwardly done using a case
expression on the operation symbol.  I have tested the case speed of
three Scheme implementations (CScheme, MacScheme and PC Scheme) and in
all of them cond is faster than case!

Since the case labels have to be symbols, shouldn't the case
expression be faster than the corresponding cond expression?  Is there
some reason why Scheme's case can't be implemted using a computed goto
like in ordinaty programming languages?
-- 
	Juha Heinanen
	Tampere Univ. of Technology
	Finland
	jh@tut.fi (Internet), tut!jh (UUCP)